METAL ABUNDANCES FROM WASHINGTON PHOTOMETRY OF GLOBULAR-CLUSTERS IN NGC-5128

Integrated photometry on the Washington system has been obtained for 62 globular clusters in the nearby peculiar elliptical galaxy NGC 5128; from these data [Fe/H] values accurate to approximately 0.25 dex have been derived based on the C-T1 index. The mean metallicity of [[Fe/H]C-T1] = - 0.8 +/- 0.2 confirms previous indications that the NGC 5128 globular cluster system is at least 0.5 dex more metal rich than that of the Galaxy. Approximately 20% of the clusters are redder than their reddest Galactic counterparts. However, the most metal-rich clusters appear to be only slightly enhanced over solar abundance and not as extreme as suggested by Frogel's infrared observations [ApJ, 278, 119 (1984)], although the difficulties in calibrating metal abundances for such clusters are formidable. Furthermore, in both range of metallicity and mean value, the NGC 5128 cluster system shows a striking similarity to that associated with NGC 1399, the central elliptical in Fornax, suggesting that the process of metal enrichment of a globular cluster system depends more on the parent galaxy's luminosity than on its environment.